Kinetic analysis of the regulation of the [Na.sup.+]/[H.sup.+] exchanger NHE-1 by osmotic shocks

Osmotic shocks are used to study the kinetics and mechanism of NHE-1 regulation, a ubiquitous, mitogen-activatable, mammalian [Na.sup.+]/[H.sup.+] exchanger that maintain cytosolic pH and cell volume. The results obtained suggested that NHE-1, allosteric equilibrium and its cooperative response to intracellular acidifications are extremely sensitive to modification of its membrane environment.